The gruesome discovery came ahead of a briefing by peace envoy Lakhdar Brahimi to the UN Security Council on the uprising, which the United Nations says has left more than 60,000 people dead.

Abu Seif, a rebel fighter, said 78 bodies were retrieved from the Quweiq River and that 30 more were still in the waters but out of reach because of regime snipers.

"The regime threw them into the river so that they would arrive in an area under our control, so the people would think we killed them," he said.